The field of the invention is that of fuel injector systems and the invention relates more particularly to fuel injectors having economical and easily applied heaters disposed on the fuel injectors for heating fuel furnished to an engine by the fuel injectors.
Conventional fuel injector systems mechanically apply energy to fuel furnished to an internal combustion engine to form a fuel spray to enhance fuel vaporization as the fuel is furnished to an engine. Adequate fuel vaporization is difficult to achieve on a cold day when cold manifolds and other engine parts withdraw heat from the fuel. Further, forming of a fuel spray in that manner can withdraw heat from the fuel and on a cold, humid day frequently results in the creation of frost resulting in blocking of the fuel injectors. This is particularly true where the fuel injectors are furnishing fuel with a significant methanol content which tends to be relatively more difficult to vaporize at the temperature levels likely to be encountered in automotive fuel injector application. Accordingly, it is desirable to employ self-regulating fuel heaters of positive temperature coefficient of resistivity for heating fuel furnished to an engine by fuel injectors to enhance fuel vaporization and avoid blocking fuel injectors by frost during fuel injection on cold, humid days. However, fuel injectors are relatively complex devices which are highly engineered to be made by volume manufacturing techniques in order to be produced at reasonable cost, and it would be desirable to provide fuel injector heaters which are economical and easily applied in fuel injector systems of various types to achieve efficient fuel heating without interfering with performance of the fuel injectors.